An analysis of the sources of heavy metals in atmospheric dustfall of Shijiazhuang City

Abstract：Fifty-one atmospheric dustfall samples were collected successively from November 2007 to November 2008 in Shijiazhuang. All dustfall samples were analyzed for concentrations of As, Cd, Hg, Pb, Cr, Cu, Zn, Ni, Mn, Mo, Al2O3 and K2O. The results indicate that, compared with the background values of soil in Shijiazhuang area, atmospheric dustfalls have elevated metal concentrations on the whole, except for the concentration of Al2O3. Correlation coefficient analysis and principal component analysis (PCA) were performed and three main sources were identified: (1) Pb, Cr, As, Hg, Mo, Cd and Mn, which are mainly derived from coal combustion and traffic pollution; (2) Ni, Cu and Zn, which are probably related not only to coal combustion but also to factory exhaust; (3) Al2O3, which is mainly derived from soil particles. Based on concentration analysis and correlation analysis, the authors selected Al as the reference element to calculate the heavy metal enrichment factors (EFs), which in turn further validated the source identification. However, industrally enhanced Cd, Hg and Zn show maximum enrichments. Therefore, EFs shed a light on the level of human influence on atmospheric dustfalls. High concentrations of heavy metals in atmospheric dustfalls are consistent with the distribution of the industrial area.